Bacteriostatic drawsheet



M 2 fimmzhafia March 1967 R. J. SCHOONMAN 3,308,488

BACTERIOSTATIC DRAWSHEFIT Filed May 3, 1965 2 Sheets-Sheet 1 FIG. 4

FIG. 2

INVENTOR RICHARD J. SCHOONMAN BY W 77 ATTORNEY March 14, 1967 R. J. SCHOONMAN 3,308,488

BACTERIOSTATIC DRAWSHEET Filed May 5, 1965 2 Sheets-Sheet 2 l/ W W W 19 Q8 2 8' 28' 28' FIG. 7

INVENTOR RICHARD J. SCHOONMAN BY 77 0 ATTORNEY United States Patent 0 3,308,488 BACTERHGSTATIC DRAWSHEET Richard J. Schoonman, 1920 E. Wendover Ave., Greensboro, N.C. 27405 Fiied May 3, 1965, Ser. No. 452,765 8 Claims. (Cl. 5335) Patented Mar. 14, 1967 found that bacteriostatic compounds including 'Actamer This invention relates to bedcoverings and, more parsoldhy Monsanto Chemical Company, and hampers ticularly, to an improved bacteriostatic or bacteria fight ing drawsheet suited for use on hospital and other beds. It has long been the practice for hospitals to utilize water-impervious rubber or plastic sheeting to protect the mattresses of their beds from the deleterious effects of water, urine, blood, etc. These protective sheets are conventionally arranged to present a smooth, flat top surface upon which the patient reclines and are quite uncomfortable to lie upon for extended periods of time, for the impervious sheeting blocks ventilation beneath the patient and tends to uncomfortably cling to the body of the patient. It, therefore, has become the practice to utilize the impervious drawsheet in combination with an overlying cotton or other pervious moisture-absorbent sheet interposed between the patient and the protective'sheet in order to promote the comfort of the patient.

Unfortunately, the overlying fabric or cotton sheet tends to increase the danger of disease through reinfection or cross-contamination by serving as a breeding place for harmful bacteria such as Staphylococcus, Streptococcus, and other related gram-positive pathogens. The cotton sheet tends to become moist from the perspiration and other wastes excreted by the patient and the body heat of the patient keeps the moist fabric warm, thereby providing highly favorable conditions for the proliferation and growth of harmful bacteria. The bacteria are amply supplied with nutrients from the body wastes of the patient, but much of the body waste is acidic, and those bacteria which prefer more neutral conditions tend to migrate through the cotton sheet toward and onto the impervious drawsheet where less acidic conditions of moisture and warmth prevail.

The rapid and continued growth of colonies of bacteria on the impervious drawsheet and the cotton sheet is dangerous not only to the patient lying on the drawsheet but also to the hospital personnel and other patients. The patient immediately involved and the hospital personnel handling the contaminated drawsheets are endangered through direct infection while other patients and personnel are endangered through cross-infection. It is the practice in many hospitals to change the overlying cotton sheet periodically without changing or sterilizing the impervious drawsheet. Unfortunately, colonies of bacteria frequently remain on the impervious drawsheet despite efforts to remove them and continue to multiply and flourish when returned to the favorable conditions of warmth and moisture.

It has been previously proposed to combat the growth of bacteria by incorporating in an impervious drawsheet a bacteriostatic agent which tends to kill or inhibit the growth of harmful bacteria. United States Letters Patent No. 2,272,397 to Becher et al. discloses a smooth rubber drawsheet which has been permeated with the vapor of oxyquinoline and, when so treated, is said to inhibit the growth of Staphylococcus aureus and other organisms. The disclosure, however, teaches that the treated rubber sheeting is to be brought into direct contact with the skin of the patient in order to obtain the beneficial effects of the bacteriostatic agent. The disclosure is obviously im practical because of the extreme discomfort encountered in lying on a smooth rubber sheet, particularly while feverish. Also, the rubber itself tends, in use, to become brittle and crack thereby impairing the water imperviousness of the sheet in addition to become more uncomphene, such as compound G1l, manufactured bfsa 10 dar Corporation of New York are compatible with polyolefins or plastics such as polyethylene and may be used to make bacteriostatic plastics which effectively kill bacterial outright or inhibit their growth.

It is an object of this invention to provide an improved impervious drawsheet formed from a polyolefin plastic and treated with a bacteriostatic agent in accordance with said Patent No. 2,919,200, and having textured surface characteristics which improve the effectiveness of the bacteriostatic agent while contributing to the flexibility of the impervious drawsheet and to the comfort of the patient.

It is a further object of the invention to provide a drawsheet of the type described which may be used in combination with a cotton sheet in the conventional manner and which will effectively retard the growth of bacteria and maintain the bacterial concentration at satisfactorily low levels.

It is'a further object of the invention to provide a drawsheet of the type described which will retain its bacteriostatic qualities through several changes of the cotton sheets.

A still further object of the invention is to prov de a drawsheet of the type described which may be produced with sufficient economies to permit it to be economically destroyed after use by a patient. The disposable nature of the improved drawsheet makes it possible to effect economies in the storage and handling of conventional impervious drawsheets.

Having set forth some of the objects of this invention, other objects and a fuller understanding of the invention may be had by referring to the claims and the following description in connection with the drawings wherein- FIGURE 1 is a perspective view of a mattress having positioned thereon a protective, bacteriostatic drawsheet according to the invention;

FIGURE 2 is an enlarged plan view of a portion of one side of the improved drawsheet;

FIGURE 3 is a sectional view taken substantially along the line 3-3 in FIGURE 2;

FIGURE 4 is a sectional view taken substantially along the line 4-4 in FIGURE 2;

FIGURE 5 is a plan view of the other side of the sheet from that shown in FIGURE 2;

FIGURE 6 is a sectional view taken substantially along the line 66 in FIGURE 5;

FIGURE 7 is a sectional view taken substantially along the line '77 in FIGURE 5.

As shown in FIGURE 1, an impervious drawsheet, textured and treated according to the invention, is positioned across the mid-portion of a sheet covered mattress 12, and held in place by tucking its ends under the mattress in the usual way. The drawsheet 10 is preferably used in combination with an overlying cotton or other air-pervious and absorbent drawsheet 14, corresponding end portions of which are tucked under the mattress. The bedcoverings may also include a blanket 16 and top sheet 18.

The textured bacteriostatic drawsheet 10 is preferably made from a water-impervious film of a polyolefin such as polyethylene which has incorporated or dispersed therein a compatible antibacterial or bacteriostatic agent such as hexachlorophene or Actamer in the manner ec ease:

1 taught by United States Patent No. 2,919,200. More particularly, the bacteriostatic agent in dry paiticulated form is preferably admixed in the range of 0.01% to 0.05% with powdered polyethylene. The mixture may be polymerized and extruded as a thin film, or alternatively, as a rod which is subsequently particulated and reextnided as a thin film in a manner well known in the plastic art. Having been extruded and calendered to any desired thickness (a 3 mil film being suggested as an example) the film may be fed, preferably while still warm, through a pair of embossing rolls which impart to the bacteriostatic plastic film the desired irregular or textured surfaces. The embossed bacteriostatic film may be cut as desired into conveniently sized drawsheet's of 36 or 45 inches by 70 inches, as shown in FIGURE 1. If desired, the embossed bacteriostatic sheet may be of a size sufficient to cover the entire mattress.

Referring to FIGURES 2 through 7, greatly enlarged portions of respective sides of a drawsheet 10 textured according to the invention are shown to clearly illustrate the intaglio pattern embossed thereon. The obverse side 17 of the said drawsheet which is desirably positioned to be the upper or bacteria contacting surface is characterized by hollow protrusions 20 optionally of diamondshaped configuration which appear in relief and are spaced from each other by a network of communicating channels 22 defined on the surface 17 by walls 2d of the protrusions 20. The other surface 17' of the sheet 10 (FIGURES 5-7) is the converse of the side 17, the said side 17' being characterized by interconnected upstanding ribs 22 defined by walls 28 of spaced-apart depressions 20' which are the reverse of the hollow protrusions 20 rising from the obverse side 17.

In use, the protrusions and depressions tend to be flattened toward a common plane and it is desirable that they be of relatively small dimensions. A satisfactory size for the diamond-shaped protrusions 20 is that which includes walls having a length of about one-sixteenth of an inch, and a satisfactory width for the channels 22 is about one thirty-second of an inch. The depressions 20' and ribs 22' are correspondingly dimensioned. The overall thickness of the 3 mil film after embossing may be about 10 mils.

Thus textured, the amount of bacteriostatic agent which is dispersed in the polyethylene from which the walls 28, 28' are made is effectively added to that present in the protrusions 20 and depressions 20 and in the channels 22 and ribs 22', thereby greatly increasing the surface area of the bacteriostatic sheet regardless of whether the sheet is positioned top side up or bottom side up. Consequently, a larger quantity of the bacteriostatic agent is exposed than in the case of a smooth surface.

In use, the bacteriostatic agent applied according to Patent No. 2,919,200 tends toleach to both the top and the bottom surfaces of the drawsheet 10 to contact any bacteria adjacent thereto and either kill outright or great- -ly inhibit their growth. Further, any bacteria-containing moisture which may collect in the channels 22 (or in the depressions 22 if the sheet be inverted) so positions the bacteria that the bacteriostatic agent in the walls 28 and in the channels 22 may more quickly reach and effectively kill or inhibit the growth of the bacteria.

Therefore, it is seen that the bacteria tending to migrate away from the acidic conditions present adjacent the patient and toward the more neutral conditions on or adjacent the protective sheet 10 are killed or growth-inhibited by the bacteriostatic agent rather than being allowed to propagate, grow and spread back toward the patient through the fabric sheet 14. Thereby, the danger of the overall concentration of bacteria in the fabric sheet 14 increasing above the dangerous infection levels is reduced. Consequently, by the textured arrangement of the prospective bacteria contacting surface of the draw- 4% sheet 10, a much more effective and improved bacteriostatic drawsheet has been provided.

The textured sheet has a further beneficial effect in that such arrangement reduces the discomfort previously experienced in lying on a smooth watenimpervious sheeting. This benefit is thought to arise from the fact that small pockets of air are disposed between the patient and the protective drawsheet.

While it is only necessary that one prospective bacteria contacting surface be textured with the pluralities of protrusions and depressions, certain beneficial side effects are noted when both the top surface and the bottom surface of the sheet 10 are textured.

First, where the sheet is textured on both sides, one need not worry about making sure that the sheet be positioned with the top side up, for either the top or the bottom side may serve as the bacteria contacting surface.

Also, it is much easier to impart the textured bacteria contacting surface to the plastic film as by embossing if both the top and the bottom sides may be textured or made irregular. Further, a thin film which has been embossed with corresponding patterns on both sides is more flexible, and, therefore, more comfortable than a thicker film embossed only on one side with correspondingly deep depressions so as to present the same total area of bacteria-contacting surface.

Moreover, a sheet is thereby provided which has both a top and a bottom frictional surface attributable to the pluralities of protrusions and depressions whereby the sheet is prevented from slipping from position on the mattress and from becoming untucked. Further, the overlying fabric drawsheet is prevented from becoming untucked by the irregular top surface.

Also, it has been found that comfort in lying upon the sheet is increased when the bottom surface is also irregular in that air is thought to become trapped under the protective sheet and, thereby, add to the resiliency of the protective sheet as positioned on the mattress.

While the sheet disclosed may be so positioned on the mattress that either side becomes the bacteria contacting surface, it is preferred that the bacteria contacting surface be characterized by protrusions spaced apart by communicating depressions, for it has been found that some air is allowed to pass between the protective sheet and the overlying fabric sheet as the patient lying thereon redistributes his weight thereby allowing some ventilation to the underside of the patient and increasing the comfort experienced in lying thereon.

Moreover, the positioning of the collapsible relief pattern toward the patient is advantageous in that it increases the effective bacteriostatic surface area presented to combat harmful bacteria.

There is thus provided an improved textured and bacteriostatic impervious drawsheet adapted for single-patient use which is capable of greatly reducing the danger of infection in hospitals.

In the drawings and specification there have been set forth preferred embodiments of the invention and, al though specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A protective bedcovering comprising:

(a) a thin film of water-impervious flexible plastic having an obverse side and a reverse side, each characterized by an intaglio design which defines a corresponding relief design on the opposite side to texture both sides of the film, and

(b) a bacteriostatic agent on both sides of the plastic film effective to kill or inhibit the growth of bacteria coming in contact with said film.

2. A protective bedcovering according to claim 1 wherein the plastic film is made from a polyolefin and wherein the bacteriostatie agent comprises hexachlorophene intimately admixed with the polyolefin.

3. A protective bedcovering according to claim 1 wherein the plastic film is made from a polyolefin and the bacteriostatic agent comprises Actamer intimately admixed with the polyolefin.

4. A protective bedcovering according to claim 1 wherein the height of the relief design on the obverse side is about equal to the thickness of the plastic film from which the bedcovering is made.

5. A protective bedcovering according to claim 1 wherein the combined height of the relief design and the depth of the intaglio design on the obverse side is about twice the thickness of the plastic film from which the bedcovering is made.

6. A protective bedcovering according to claim 5 wherein the relief design on the obverse side comprises a repeat pattern of closely spaced diamond-shaped elements and the intaglio design on the obverse side comprises a network of interconnected channels separating the diamond-shaped elements. I

7. A protective bedcovering according to claim 6 wherein the intaglio design on the reverse side comprises a repeat pattern of diamond-shaped elements and the relief design on the reverse side comprises a network of interconnected ribs separating the diamond-shaped elements.

8. A protective bedcovering according to claim 7 wherein the diamond-shaped elements are uniformly dimensioned in size and measurable as a fraction of an inch, and wherein the ribs and channels are similarly dimensioned.

References Cited by the Examiner UNITED STATES PATENTS 2,250,480 7/1941 Gump 167-31 X 2,272,397 2/1942 Becher 260-768 2,919,200 12/1959 Dublin et al. 106-15 3,053,252 9/1962 Wolf l28296 X 3,096,183 7/1963 Genth 167-42 X FRANK B. SHERRY, Primary Examiner.

A. CALVERT, Assistant Examiner. 

1. A PROTECTIVE BEDCOVERING COMPRISING: (A) A THIN FILM OF WATER-IMPERVIOUS FLEXIBLE PLASTIC HAVING AN OBVERSE SIDE AND A REVERSE SIDE, EACH CHARACTERIZED BY AN INTAGLIO DESIGN WHICH DEFINES A CORRESPONDING RELIEF DESIGN ON THE OPPOSITE SIDE TO TEXTURE BOTH SIDES OF THE FILM, AND (B) A BACTERIOSTATIC AGENT ON BOTH SIDES OF THE PLASTIC FILM EFFECTIVE TO KILL OR INHIBIT THE GROWTH OF BACTERIA COMING IN CONTCT WITH SAID FILM. 